Dynamic susceptibility contrast (DSC) Magnetic Resonance Imaging (MRI) is a technique of perfusion scanning using an MRI system wherein a contrast reagent (CR), such as a gadolinium-based contrast reagent (Gd CR), is injected and a time series of fast T2*-weighted images are acquired. DSC MRI with Gd CR has become one of the imaging standards for brain perfusion measurement and the depiction and detection of brain tumors.
Relative cerebral blood volume (rCBV) has been shown as a very useful imaging biomarker for brain tumor diagnosis, prognosis, and treatment/therapy response monitoring. Software packages like Nordic ICE 4 with Food and Drug Administration (FDA) 510 k clearance further illustrate the clinical relevance of rCBV. DSC MRI with low molecular weight Gd CR is often the method of choice for rCBV quantification.
However, DSC MRI with Gd CR is often confounded by CR leakage into brain tumor interstitium space, e.g., Gd CR leaks out of the vascular space when the blood brain barrier is compromised. Several model-based and model-independent leakage correction methods have been proposed. Examples of model-independent leakage correction approaches are described in Paulson E S and Schmainda K M, Radiology 249 601-613 (2008); and Emblem K E et al, J Cereb Blood Flow Metab 31, 2054-2064 (2011); both of which are incorporated by reference herein.
Using such approaches, pharmacokinetic indication of a corrected “leakage rate constant” remains to be clearly defined and the variable influence of the transient phase during CR first pass often further complicates rCBV calculations. In addition, effects of mixed T1/T2* weighting exhibited in the tails of DSC MRI time-courses are often subjected to further corrections thereby increasing computational time while providing inaccurate leakage correction results. Further, current FDA 510 k cleared packages for DSC MRI calculations provide options that either do not correct for Gd CR leaking into a brain lesion area or options that overcorrect Gd leakage. The result is a degraded diagnostic capacity of the DSC MRI. Thus, an optimal leakage correction approach remains to be properly identified for Gd CR.